MMT AO run Jan 13 — 23

MMT AO run Jan 13 - 23

• Timeline: – Night 1: Install hardware during MMT engineering – Nights 2 -4: AO engineering with fast-framing H camera (Indigo) – Nights 5 -7 (nominally): ARIES commissioning • The good – ARIES mounts just fine and makes focused images. • The bad – Images are badly astigmatic, and the entrance window was cracked while trying to fix this. The detectors are OK, but we still don’t understand where the astigmatism came from. – Night 7: More imaging with Indigo camera – Nights 8 -10: Imaging/nulling with BLINC/MIRAC – Night 11: Lost to bad weather and PSU failure

System view • Overall the system runs very sweetly at 550 updates per sec. • Currently we correct the lowest 52 modes of the aberration (sufficient to get the diffraction limit at H in good seeing). • Integration time can be slowed down arbitrarily to give access to fainter guide stars. • Ability to dial static aberration into the WFS to clean up DC errors in the science focal plane.

Secondary mounted and ready to go, November 2002. Takes 1. 5 hr and 2 people to mount and dismount (currently requires Francois Wildi and Michael Lloyd-Hart). WFS top box is also straightforward to mount.

Challenges that surfaced • Loss of ARIES was a blow – we need to understand the source of astigmatism before we rebuild the dewar’s front end in case design changes are needed. • Installation of the system is now faster than f/9 although post-installation alignment must still be sped up. • WFS read noise is WAY too high (> 30 e-). Limits us to stars > V ~ 10. • Internal alignment of the WFS must be automated to guard against flexure w/ gravity. • Image jitter is seen at 19 and 38 Hz at the level of 20 mas. This currently limits our Strehl.

Power in one-axis image motion

Current operational constraints • Takes two people (Doug Miller and Guido Brusa) to run the system. • Installation requires a team of ~6 people. • Guide star brightness must be < 10 (we hope this will improve by several magnitudes before our next run). • Still some single point failures that must be addressed (e. g. power supplies).

Future • Most of the hardware has been left at the mountain (it works, so no need to move it). • Problems with WFS sensitivity, optical alignment and image jitter are to be addressed in the next 4 months. • We would like another run in May devoted largely to engineering, demonstrating closed loop on fainter stars and improved robustness/ observing efficiency. • Use PISCES to demonstrate K band diffraction limit (not seen yet).